Drug-related morbidity and mortality cost the United States over $177.4 billion annually and are especially daunting among the elderly. To improve pharmacotherapy outcomes and reduce costs, the Centers for Medicare & Medicaid Services (CMS) established medication management therapy (MTM) programs as part of the Medicare prescription drug benefits (Part D) in 2006. Unfortunately, MTM enrollment has fallen below CMS targets mainly due to issues in MTM program design. Further, based on our previous policy scenario analysis, primarily supported by an NIA R01, MTM eligibility criteria may be too restrictive for racial/ethnic minorities and may perpetuate racial/ethnic disparities in health outcomes, because MTM eligibility is based on utilization of medications, which minorities tend to use less. CMS attempted to relax MTM eligibility thresholds, citing our research, but potential disparities remain with the utilization-based eligibility criteria. A critical barrier to effective MTM reform is the lack of stronger information about the actual effects of MTM on minorities' outcomes, utilization of MTM by minorities, and the cost-effectiveness of MTM. We will fill this knowledge gap through our proposed research with newly available MTM data. Our long-term goal is to improve the health status of older adults among diverse populations by improving medication utilization and reducing racial/ethnic disparities in medication utilization and health outcomes. We will analyze Medicare Parts A/B/D data (2015- 2016), linked to Area Health Resources Files. Our expected outcomes include new information on: (1) effects of MTM on racial/ethnic disparities in medication utilization, utilization/costs of health services, and mortality; (2) measures of MTM utilization, such as MTM delivery methods, that exhibit disparity patterns; and (3) cost- effectiveness of MTM from the perspectives of Medicare and health system. We will measure medication utilization using evidence-based statin prescribing and other measures primarily developed by Pharmacy Quality Alliance and adopted by Star Ratings, a health-plan-quality evaluation system tied to CMS bonus payments to Part D plans. Utilization/costs of services include those of physician visits, emergency room visits, and hospitalizations (e.g., hospitalizations originating from ambulatory care sensitive conditions). We will apply multivariate regression models, a difference-in-difference strategy and negative benefit regression models using frequentist and Bayesian approaches. Aim 1: Test the hypothesis that MTM programs have reduced racial/ethnic disparities in quality of medication utilization, and health services utilization and costs. Aim 2: Test the hypothesis that non-Hispanic Blacks and Hispanics receive fewer and delayed MTM services than Whites. Aim 3: Test the hypothesis that MTM is a cost-effective program. Impact: Our results will provide much- needed empirical evidence to guide MTM policy-making by CMS, and assist the NIA/NIH in its strategic goals of informing ?policy decisions? and ?understand(ing) health disparities and develop(ing) strategies to improve the health status of older adults in diverse populations.?